Distribution of buffalograss polyploid variation in the southern Great Plains

Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] is indigenous to the sho rt-grass prairies of North America and is a polyploid series of diploid, te traploid, and hexaploid individuals. It has a base chromosome number of x = 10. The distribution pattern of these ploidy levels is not well-defined, e specially in the southern Great Plains. We predicted the ploidy levels of 2 73 buffalograsses from the southern Great Plains of North America using flo w cytometry to measure cellular DNA content. The buffalograss accessions we re grouped into four distinct ploidy level groups. Very few diploid accessi ons were collected (2.6% of the collection), and all were found in northwes t Texas and eastern New Mexico. Tetraploid accessions (23% of the collectio n) were found exclusively in the western regions of the southern Great Plai ns. Hexaploids were the most prevalent ploidy level, representing 73% of th e collection and found throughout the collection area. Pentaploid accession s were also found in field sites (1.8% of the collection). No clear pattern of adaptation for ploidy levels is apparent from these data. In other coll ections, cold hardiness appears associated with higher ploidy levels, but t his pattern is not apparent in the southern Great Plains.